基于嵌入式的高精度简易电子秤的研制

Development of High Precision and Simple Electronic Scale Based on Embedded System

为研制一种具有物体称重、键盘输入、价格计算、显示、指示等功能的高精度简易电子秤,以TI公司32位单片机TM4C123GXL作为嵌入式主控核心。利用电阻应变式称重传感器的全桥式称重原理,及通过受力改变内部应变片的阻值使电路的输出电压与传感器所受压力成线性关系,建立相应数学模型。对传感器所测得的电压值进行模数转换,并将此转换数值与具体重量相对应,再把最终数值通过TFT彩屏实时显示。称重传感器在受压时形变量小从而使得输出电压信号微弱。故采用运放连接成差分放大电路,将其微弱信号进行放大处理再通过ADC将此模拟量转化为数字量,再输送给单片机。结果表明:该电子秤具有精度高、工作稳定等优点,实现了物重快速检测功能。

In order to develop a high-precision simple electronic scale with object weighing,keyboard input, price calculation,display,indication and other functions, TI 32-bit microcontroller TM4C123GXL is used as the core of embedded control.By using the full bridge weighing principle of the resistance strain gauge load cell, and by changing the resistance of the internal strain gauge by force,the output voltage of the circuit is linearly related to the pressure of the sensor,and the corresponding mathematical model is established.ADC value of the voltage measured by the sensor,and the conversion value and specific weights,then the final value by TFT color display.The weight sensor is small in shape when it is pressed,so that the output voltage signal is weak.So the operational amplifier is connected to a differential amplifying circuit to amplify the weak signal,and then the analog quantity is converted to digital quantity through ADC.And it is transmitted to the single chip microcomputer.The results show that the electronic scale has the advantages of high precision,stable work and so on,and realizes the rapid detection of the weight.